THERMODYNAMICS OF METHACRYLATE SYNTHESIS FROM METHANOL AND A PROPIONATE

Methacrylate monomers can be formed by the reaction of methanol and a propionate, e.g., propionic acid, propionic anhydride, or methyl propi onate. Formaldehyde, a necessary reaction intermediate, can be produce d from methanol via either dehydrogenation or partial oxidation. The e quilibrium compositions for several variations of this chemistry were calculated as a function of temperature, total pressure, and inlet com position using a free-energy minimization technique. The thermodynamic analysis revealed that the methanol dehydrogenation route gave higher propionate conversion and selectivity than the partial oxidation alte rnative. For the dehydrogenation route, both conversion and selectivit y were favored by high temperature and high methanol/propionate feed r atio. The calculations also showed that a methyl propionate feed produ ces the least amount of water and diethyl ketone, two byproducts which can complicate any process design for this chemistry.